Because relatively few children with mental health problems are treated in the tertiary mental health system, improving the treatment of children seen in primary care is essential, especially for conditions like attention deficit hyperactivity disorder, that respond well to medications that primary care physicians can manage. Community medical treatment of ADHD, however, is less then optimal. The proposed study examines whether the use of stimulant medication by community pediatricians can be improved. The specific aims of this study are to determine, in a randomized trial: 1) If specialized training for pediatricians in the use of stimulant medications for ADHD improves the classroom and at-home behavior of children with ADHD who are seen in primary care; 2) If specialized training and assistance in monitoring stimulant medications improves pediatrician's prescription and monitoring practices, and conformity to practice standards for managing ADHD; 3) The costs associated with training and changes in practice management procedures for managing ADHD as they relate to improvements in symptoms. This study proposes a randomized trial of treatment and monitoring procedures to improve the use of stimulants in primary care pediatric settings. In the specialized pediatric care group, pediatricians and nursing staff will be trained in the use of an algorithm-based titration and treatment protocol for stimulant medications, and in appropriate monitoring procedures. In the usual-care group, the pediatrician will be notified if the child has ADHD, with the physicians managing those patients in whatever manner the physician deems most appropriate. Assessment of patient responsiveness to treatment will be made at baseline, 4-, 9-, and 12-months after treatment initiation using teacher and parent reports of behavior change and classroom observations. Changes in practice procedure, frequency of visits and costs for training and providing specialized care will be examined. Following an intent-to-treat model, a minimum of 468 children (234 SC; 234 TAU) will be recruited and complete all evaluations in the intensive training phase.